Dendrobium genus was reported to contain alkaloid, bibenzyl, fluorenone, phenanthrene, sesquiterpenoid, and phenolic acid, which have biological properties. Our aim was to investigate the protective effect of an aqueous extract of Dendrobium nobile Lindl (DNE) against cisplatin-induced acute kidney injury (AKI). Quantification of four phenolic acids (4-hydroxybenzoic, vanillic, syringic, and ferulic acid) in DNE was determined using the HPLC-photodiode array method. Possible protective effects against cisplatin-induced nephrotoxicity were investigated using in-vitro (porcine kidney cells; PK15) and in-vivo (Sprague Dawley rat) studies. Among the four phenolic acids, 4-hydroxybenzoic acid was the most abundant. In the in-vitro study, DNE pretreatment partially prevented decrement of viability after cisplatin (15 μg/mL) treatment in the both the MTT and crystal violet assays. Moreover, relative to cells treated with cisplatin alone, the DNE (50 μg/mL)-pretreated cells showed a ~30% increase in glutathione levels and a ~15% decrease in reactive oxygen species. The expression of p53 was also decreased in DNE-pretreated cells (p < 0.05). In the in-vivo study, the renal function index decreased to normal levels in groups pretreated with DNE (300 and 500 mg/kg); histopathological alterations and apoptotic cells were also attenuated. Moreover, DNE pretreatment ameliorated oxidative stress in the kidney, as evidenced by recovered antioxidant enzyme levels and decreased lipid peroxidation. DNE, by decreasing oxidative stress, was found to have a protective effect against cisplatin-induced nephrotoxicity. Based on these findings, DNE might be beneficial when treating cisplatin-induced AKI.